1. Stir togetherthe cornstarch and sugar, and place in a saucepan. Stir in the evaporated milk and chocolate chips. Cook over medium heat until chocolate is melted and the mixture is thickened. Stir constantly to prevent burning.
2. Remove from heat and stir in the yogurt and vanilla. Put in the refrigerater until thoroughly cold.
3. Pour the mixture into an ice cream maker and freeze according to the manufactuers instructions.
4Scoop out and serve with or without a garnish to make a very delicious Homemade dessert, and have friends asking for the recipe.